What is WhatsApp's 24-hour service window?

It is the 24 hours after a customer messages your business number, during which you may reply without an approved template and without a per-message charge. Tiram shows the exact expiry time per customer on the Contacts screen.

Does the window reopen if I message the customer again?

No. Only a message from the customer opens or extends it. Your own sends do not.

What words does a customer send to stop messages?

STOP, UNSUBSCRIBE, CANCEL, OPTOUT or OPT OUT. Any of them opts the customer out immediately and excludes them from campaigns, reminders and receipts.

How does a customer start receiving messages again?

They reply START, SUBSCRIBE, UNSTOP, OPTIN or OPT IN, and are opted back in automatically. A staff member can also record consent from the Contacts screen; either way the date and the source are kept.

Do I have to raise my daily sending limit myself?

No. Meta sends the new cap over the webhook and Tiram updates your tier from it, so a raised limit takes effect without anyone editing a setting.

Can I reply to a customer's WhatsApp message inside Tiram?

No — Tiram is not a chat inbox. It logs the reply and the free-reply deadline; you answer from WhatsApp Business on the shop phone, on the same number.

Reference

The 24-hour window, STOP, START and daily limits

The short answer

When a customer messages your WhatsApp Business number, Meta opens a 24-hour service window during which you can reply freely — no approved template needed, and no per-message charge. Tiram records every inbound message, shows how much of that window is left on the Contacts screen, and honours STOP and START replies automatically.

The terms, and what each means in practice

These are Meta's rules, not Tiram's. What is ours is how faithfully they are enforced and how visible they are to you.

WhatsApp Business messaging rules and how Tiram applies each one.
Term	What it means	How Tiram handles it
Service window	24 hours from the customer's most recent message to you, during which a reply is free and needs no template.	The Contacts screen shows Free until with the exact time, or a dash when the window has closed.
Inbound message	Anything the customer sends you — text, a photo, a voice note, a location.	Every one is recorded, including the non-text kinds, and the activity feed names the customer who sent it.
STOP	The customer's own opt-out. Recognised words: STOP, UNSUBSCRIBE, CANCEL, OPTOUT, OPT OUT.	Opts them out immediately and excludes them from every campaign, reminder and receipt from that moment.
START	The customer changing their mind. Recognised words: START, SUBSCRIBE, UNSTOP, OPTIN, OPT IN.	Opts them back in without anyone phoning the shop, and records that they asked for it themselves, with the date.
Messaging tier	Meta's cap on how many conversations your number may start per day: 250, 1,000, 10,000, 100,000 or unlimited. It rises as your number keeps a good quality rating.	Sends are gated against your current tier, and the tier updates itself when Meta raises it — nobody has to edit a setting.
Utility vs marketing	Meta prices and polices the two categories differently: utility for a bill, a receipt or a balance; marketing for an offer.	Each category has its own spend ceiling you set, so a marketing blast can never eat the budget your invoices need.

The numbers worth knowing

Four figures decide what a WhatsApp channel can and cannot do on any given day.

Free reply window: 24 hoursMeasured from the customer's last message, not from your reply. Sending again later restarts nothing.
Messaging tiers: 250 → unlimitedFive steps: 250, 1,000, 10,000, 100,000, unlimited business-initiated conversations per day.
Ways to opt back in: TwoThe customer replies START, or a staff member records the consent from the Contacts screen. Both are stamped with a date.
Spend ceilings: One per categoryUtility and marketing are capped separately, over a daily, weekly or monthly window that resets itself.

Rules Tiram enforces on every send

The point of naming these is that you can predict what will happen before you press send.

Outside the window, a template is mandatory: Any message that starts a conversation — an invoice, a reminder, a campaign — uses a template Meta has approved. That is Meta's rule, and it is why the templates screen exists.
STOP always wins, even for a bill: Meta technically permits utility messages to an opted-out customer. Tiram refuses anyway: one report from an annoyed customer damages the number quality every other message depends on.
Consent has provenance, not just a flag: When consent is explicit, Tiram keeps how it happened and when — asked to receive messages on 12 Jun or consent recorded by your team on 12 Jun — so a Meta quality review can be answered with a record instead of a shrug.
A tier rise is picked up automatically: Meta announces a new daily cap over the same webhook that carries delivery receipts. Tiram reads it and updates the tier, so you are not throttled by a stale setting after Meta has already raised your limit.
Every inbound message is kept, not just the ones we understand: A photo or voice note that carries no keyword is still recorded. Discarding it would leave a gap in the log at exactly the moment a customer engaged with you.
Tiram is not a chat inbox: It records that a customer replied and how long you have to answer free. The reply itself you write in WhatsApp Business on the shop phone — which is exactly what coexistence keeps possible on the same number.

Three assumptions worth correcting

Each of these costs money or goodwill when believed.

The 24 hours restart every time I send a message.
The window is measured from the customer's last message to you. Your own sends don't extend it — only their reply does.
An opted-out customer still gets their bills, because those are utility messages.
Not in Tiram. Invoices, receipts and reminders all skip an opted-out customer, and a bulk run reports how many were skipped for that reason.
After Meta raises my limit, someone has to update it in the app.
The new cap arrives over the webhook and the stored tier updates itself. The setting exists, but it is not something you have to maintain.

Which plan includes WhatsApp messaging

Everything on this page belongs to Tiram's WhatsApp module, included on the Gold and Platinum plans. The Silver plan has no WhatsApp sending, so no window, tier or consent handling applies to it.

On the offline Windows/Mac desktop app the same gate applies, with one platform difference worth knowing: a desktop install has no public address for Meta's webhook, so inbound replies, delivery receipts and automatic tier updates are unavailable there — sends still work, and their status stops at Sent.

FAQs

What is WhatsApp's 24-hour service window?: It is the 24 hours after a customer messages your business number, during which you may reply without an approved template and without a per-message charge. Tiram shows the exact expiry time per customer on the Contacts screen.
Does the window reopen if I message the customer again?: No. Only a message from the customer opens or extends it. Your own sends do not.
What words does a customer send to stop messages?: STOP, UNSUBSCRIBE, CANCEL, OPTOUT or OPT OUT. Any of them opts the customer out immediately and excludes them from campaigns, reminders and receipts.
How does a customer start receiving messages again?: They reply START, SUBSCRIBE, UNSTOP, OPTIN or OPT IN, and are opted back in automatically. A staff member can also record consent from the Contacts screen; either way the date and the source are kept.
Do I have to raise my daily sending limit myself?: No. Meta sends the new cap over the webhook and Tiram updates your tier from it, so a raised limit takes effect without anyone editing a setting.
Can I reply to a customer's WhatsApp message inside Tiram?: No — Tiram is not a chat inbox. It logs the reply and the free-reply deadline; you answer from WhatsApp Business on the shop phone, on the same number.